Every language and culture has a word or expression that is hard to translate to other languages because they are strongly tied to the cultural context they were born in. One of the most internationally popular, for example, is the Spanish word "manana" (read "manyana") literally meaning "tomorrow". Pronounced in the right moment it means "Do not hurry, it can be done at any time later". Another useful word is Arabic "khalas". It must be pronounced strongly with a trace of anger because it means "Stop, no more discussions, no more actions in the given direction".
Do you know similar "non-translatable" words and expressions characteristic to a culture, language or community? Tell us about them and/or about confusions they caused in a different environment.